Check valves conventionally are used in applications where it is desirable to allow a flow of fluid in one direction and to prevent flow in the reverse direction. For instance, a check valve (or one-way valve) is used to prevent the backflow of water from a residence or business into a public water supply to avoid the risk of contaminating the water supply and incurring potential health hazards.
To achieve the function described above, check valves typically have a movable valve member which is seated on a valve inlet and/or a valve outlet when the check valve is in a closed or shunted position. When the valve member is unseated from the respective inlet or outlet, the check valve is opened and a "forward" flow is induced.
An inlet valve member typically is constructed so that it is unseated only in response to fluid pressure on the upstream side of the inlet, whereby a "backflow" on the downstream side of the inlet is ineffective to unseat the inlet valve member and open the valve. Similarly, an outlet valve member is constructed so that it is unseated only in response to fluid pressure on the upstream side of the inlet, whereby a "backflow" on the downstream side of the outlet is ineffective to unseat the outlet valve member and open the check valve.
It generally is known to employ, redundantly, both an inlet valve member and an outlet valve member to achieve a preferred degree of reliability in a check valve. In prior constructions the valve members have been arranged "in-line" in a housing such that the valve members are movable along a common axis to alternatively open and close the check valve.
It has become desirable to provide a check valve in which an outlet flow is discharged from the valve in a direction substantially perpendicular to the direction at which an inlet flow enters the valve. Angled check valves have been developed in response to the demand. An angled check valve embodies a substantially L-shaped flow path wherein a flow enters the check valve in a first direction and exits the check valve at a direction ninety degrees from the inlet direction.
Prior angled check valves have an inlet valve member and an outlet valve member positioned in an in-line arrangement, with each valve member being movable along a longitudinal axis in the valve housing. The axis along which the valve members are movable is aligned with either the outlet flow direction or the inlet flow direction. Because the valve housing must also provide a transverse port for directing the other of either the outlet flow or the inlet flow through the housing, the housing necessarily is, undesirably, quite large or long. In addition to the burdens imposed by the inherent excess weight and cost associated with a large check valve housing, such a check valve often is unsuitable for use in applications having restrictive envelope requirements.
The present invention is directed toward overcoming one or more of the problems set forth above.